They might be known as the "knock-knock" burglars, but police say they're no joke.

Los Angeles authorities are trying to track down the owners of more than 11,000 items recovered from burglary suspects busted earlier this year, the L.A. Times reported.

The suspects in the string of burglaries were nicknamed "knock-knock" burglars because they typically knocked on a person's door or business to see if anyone was inside before breaking in.

Police officials in June asked for help in identifying more than 3,000 high-end jewelry pieces and watches recovered from a Beverly Hills home that they believe are tied to a rash of home burglaries across the San Fernando Valley and Glendale.

Police have said the burglars belonged to a criminal group made up of South Los Angeles gang members that was targeting the affluent neighborhoods.

At least 50 people were arrested earlier this year in connection with the knock-knock burglaries, police said, and after serving search and arrest warrants, authorities discovered thousands of items they believe were stolen.

People who recognizes their property on the LAPD website can email police or leave a message at (818) 644-8091 with information about the item and incident, along with a contact number.

-- Kate Mather, Los Angeles Times, with reports from Times Community News